I am working on a new payment system with has the ability to have rewards, reviewed Bob McElrath initial white paper for Ribbit.me, I think to have a chain that support’s reward would just be a rebate. When a payer pays for an item there is a certain amount return to the original payer. The trivial would be a wallet / payment gateway which has an API for payments using an account rather than BTC address that would split the payment to the merchant and the rewards acquired.

A wallet which has an information on how much BTC or USD with the corresponding rewards that can be converted to BTC or USD which has an ability to purchase goods and merchandise.